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The alarm had just gone off, and I was lying awake at 3:59 a.m. when I felt a rumbling that rattled our whole building. It felt unusual so I had the thought that it might be an earthquake. Then I remembered that we were to have a lot of snow overnight and so I figured it was a snowplow going down the street. I was hoping it was an earthquake because I slept right through our last quake in 2008.
Sure enough, I heard on the radio that it was an earthquake, and it was centered near Gilberts, Ill., west of Chicago. It registered only 3.9 on the Richter scale. Most of the seismic activity around here is located about 300 miles south of Chicago, so it was unusual to have an epicenter in Chicagoland. A quick, unscientific check of fault maps doesn't seem to show even a little one near Gilberts (between the Wisconsin Arch and the "Des Plaines" item on the fault map).
The Haiti earthquake had just reminded me of the New Madrid (pronounced MA-drid) seismic zone along the Mississippi River. We have earthquake insurance on our building, for example, and it's because of New Madrid that we do--and justifiably so. A massive temblor struck the area in 1812 and rang church bells as far away as Boston and changed the course of the Mississippi River. The fault, the Reelfoot Rift, was formed on Rodinia, a supercontinent that encompassed the Earth's entire landmass 750 million years ago (note for future fantasy basketball team names: Rodinia Globetrotters).